C++ High Performance

Value semantics

C++ supports both value semantics and reference semantics. Value semantics lets us pass objects by value instead of just passing references to objects. In C++, value semantics is the default, which means that when you pass an instance of a class or struct, it behaves in the same way as passing an int, float, or any other fundamental type. To use reference semantics, we need to explicitly use references or pointers.

The C++ type system gives us the ability to explicitly state the ownership of an object. Compare the following implementations of a simple class in C++ and Java. We start with the C++ version:

// C++class Bagel {public:  Bagel(const std::set<std::string>& ts) : toppings_(ts) {}private: std::set<std::string> toppings_; ...